fornication

noun

for·​ni·​ca·​tion ˌfȯr-nə-ˈkā-shən 

: consensual (see consensual sense 2) sexual intercourse between two persons not married to each other compare adultery

Did you know?

What’s the difference between adultery and fornication?

In case you were wondering, the words adultery and adult are not etymologically related (in other words, adultery didn’t grow out of adult in the way that punditry grew out of pundit). Although both words come from Latin and share the same first five letters, adultery is from adulterāre (“to pollute, defile, commit adultery”), a word formed ultimately from the Latin elements ad- “to, near” and alter “other.” English adult comes from adultus, which is the past participle of the Latin word adolescere (“to grow up”).

In legal use there is a difference between adultery and fornication. Adultery is only used when at least one of the parties involved (either male or female) is married, whereas fornication may be used to describe two people who are unmarried (to each other or anyone else) engaging in consensual sexual intercourse.

Examples of fornication in a Sentence

Recent Examples on the Web

Having struck out with Nicholas, Laura is forced to return to her old tactics: impeding fornication. —Rafaela Bassili, Vulture, 10 Sep. 2025

Songs were also frequently flagged as dance music—while authorities viewed singing as having a proper place in praising God, dancing was totally forbidden as a gateway to fornication. —Livia Gershon, JSTOR Daily, 9 May 2025

If the apparent maidservant was actually a man committing fornication that might lead to another servant’s falling pregnant, then Hall was a materially destabilizing influence in the community. —Rebecca Mead, The New Yorker, 26 Aug. 2024

Cleon is in the throes of hot, sweaty fornication with his robot aid, Laura Birn's Eto, when a group of assassins infiltrate his quarters and attack. —Nick Romano, EW.com, 10 July 2023

Charlotte, Harry, Lisa, and Herbert are gathered to send their kids off to summer camp, guaranteeing a few weeks of unfettered fornication. —Aimée Lutkin, ELLE, 6 July 2023

Word History

Etymology

Middle English fornicacioun "unsanctioned sexual intercourse, sexual relations between two unmarried persons," borrowed from Anglo-French & Late Latin; Anglo-French fornicaciun, borrowed from Late Latin fornicātiōn-, fornicātiō "illicit sexual intercourse," from fornicāre "to consort with women who provide sex for money" + Latin -tiōn-, -tiō, suffix of verbal action — more at fornicate

First Known Use

14th century, in the meaning defined above

Rhymes for fornication

• abdication
• aberration
• abjuration
• abnegation
• abrogation
• acceptation
• acclamation
• acclimation
• accusation
• activation
• actuation
• acylation

Kids Definition

fornication

noun

for·​ni·​ca·​tion ˌfȯr-nə-ˈkā-shən 

: sexual intercourse between two people who are not married to each other

Medical Definition

fornication

noun

for·​ni·​ca·​tion ˌfȯr-nə-ˈkā-shən 

: consensual sexual intercourse between two persons not married to each other

Legal Definition

fornication

noun

for·​ni·​ca·​tion ˌfȯr-nə-ˈkā-shən 

: consensual sexual intercourse between a man and especially single woman who are not married to each other

also : the crime of engaging in fornication compare adultery

Note: Where still considered a crime, fornication is classified as a misdemeanor.

Etymology

Late Latin fornicatio, from fornicare to have intercourse with prostitutes, from Latin fornic-, fornix arch, vault, brothel